A term originally used to describe someone who constantly derides others success, can be on an individual basis or directed towards an organization or sports team.

Most common though, the term is used by fans of organizations whose actions are unethical or illegal enough to warrant such "hating", and accuse people of being haters instead of actually defending their team.

Jets Fan: The New England Patriots are cheaters, they should have their titles taken away!
Patriots Fan: OMG U A HATER!

Bears Fan: The Indianapolis Colts are a bunch of softies with bandwagon fans. They're a stolen team whose president changed the rules just so passing is easier.
Colts: NOT LISTENING CUZ U A HATER

Bears Fan: Brett Favre is overrated. All he does is throw interceptions in playoff games. He needs to retire, because he's just playing for personal glory now.
Packers/Vikings: U JUST A JEALOUS HATER!

A term used by others, usually being suburban "gangsters", whose lives are absolutely and undeniably defined by what others think. These people "rumble" often and think of themselves as original and/or indestructable. People that use the term "haters" are the lowest stage of the evolutionary scale. They bleed the fastest and have thought processes similar to that of a mentally underdeveloped cat.

A person that develops a strong dislike for another, solely basing their own opinion on personal judgment rather than objective merit. The formation of a hater's contempt commonly arises from jealously and/or resentment. Individuals that make fun of, or "hate," others for justified reasons cannot be legitimately classified as "haters;" although many faggots attempt to rationalize their own situations by doing so. Additionally, the word "hater" is frequently overused, mainly by members of the rap and hip-hop communities.

John is a hater of the 'Jersey Shore' MTV cast because they have more money than him, not because they are incredibly fucking annoying.

A person who feels anger and/or jealousy for someone who has succeeded in something they have worked hard for.
A being who speaks badly,and/or takes negative actions in attempt to create problems for a successful person.

When you make it out the hood,a friend can turn into a hater.
"T-Bo" dropped a dime on "Big Mike" just because Big Mike was makin some change! T-Bo a hater!